Nowadays a PDA phone or smart phone can integrate the functions of a mobile phone and a personal digital assistant (PDA) to provide mobile communication and mobile data processing functions. As operation of functions of mobile communication and data processing are different, the PDA phone or smart phone also has to provide different operation modes for these two functions.
The mobile phone function has to include a display screen and a phone keypad. The display screen aims to provide related information for mobile communication, including incoming and outgoing phone calls numbers, service provider information, short messages, and the like. The phone keypad aims to take calling phone, dial phone numbers, and edit short messages according to input methods dedicated to the phone keypad.
The PDA has to include a touch screen to display information. Input is mainly performed by direct selection from a menu on the screen through a stylus and a proprietary PDA program. Input of characters may be done by hand writing through the stylus and the touch screen, or done by a virtual keyboard on the screen. An external QWERTY keypad may also be used to enter input like on a personal computer. In order to speed up input on the PDA, besides the QWERTY keypad, also being developed are hosts with flip covers like miniature notebook computers. Such devices have a display screen and a host body that are separated and hinged on the body. The host body has a QWERTY keypad. When in use, the host may be placed on a desktop, and the display screen may be flipped upwards on the elongated side of the host body to make data entry on the QWERTY keypad easier. For instance, CD-616 and CD-72 electronic dictionaries produced by INVENTEC BESTA Co., Ltd. (reference can be found in http://www.besta.com), MD1000 electronic dictionary produced by INSTANT-DICT Co., Ltd. (reference can be found in http://www.instant.com.tw), Jornada 720 Handheld PC computers produced by Hewlett-Packard Development Company, L.P. (reference can be found in http://www.hp.com) and Zaurus SL-C3000 handheld PDA produced by Sharp Co. (reference can be found in http://ezaurus.com) are portable data processing devices equipped with QWERTY keypads that look like miniature notebook computers.
To meet the requirements of multimedia applications (such as games, videos, movies, music, and the like) and mobile communication, many manufacturers have introduced flip mobile phones or PDAs that integrate multiple functions, such as MOTORLA model V600 mobile phone (reference can be found in http://www.motorola.com), NOKIA model 7270 mobile phone (reference can be found in http://www.nokia.com). The flip mobile phone or PDA provides a larger display screen or other operation modes (such as including a keypad for data entry). The flip mobile phone has a phone keypad on the host and a flip cover containing a display screen. The flip cover is coupled on the top end of the host through a one-way hinge for opening or folding relative to the host. Although the flip cover can accommodate a larger display screen, the one-way hinge allows the flip cover to swivel only one way, thus limiting the operation mode and creating many inconveniences. For example, when using the keypad for data entry the keypad is narrow and suitable for only one hand input operation after the flip cover is opened, so input speed is limited. Moreover, the keypad mostly adopts a design with shared keys for the phone keypad and QWERTY keypad. Built-in firmware or software must be included to switch the setting for varying input requirements. If a stylus is used to operate on the touch screen, the keypad on the host cannot be hidden behind the display screen. Unconsciously hitting the buttons often occurs and results in interference to the touch screen.
These days many new mobile phones are equipped with dynamic video and still photography functions. To provide a desired photo mode or other operation modes, the mobile phone with a host and a flip cover coupled by a biaxial hinge has been developed. Reference can be found in U.S. patent publication Nos. 20040110529, 20040132482, 20040192422, and 20040198474. These all provide a mobile phone equipped with a biaxial hinge to enable the flip cover to be swiveled about two rotational axes relative to the host so that the display screen may be turned with its back side folding over the host. Therefore the mobile phone may be used like a digital camera.
As the PDA phone or smart phone that integrates the functions of mobile communication and PDA generally adopts the structure of the mobile phone or PDA, the biaxial hinge mentioned above is also used on the PDA phone or smart phone to provide different operation modes. For instance, to use the mobile phone function, the flip cover is generally lifted so that the phone keypad may be used for operational control, and the phone is moved close to the user's face during the phone conversation. To use the PDA in a handheld operation mode, the functions of the operation are performed by touching the display screen with the stylus. The host body becomes an obstacle in such a situation, so the display screen may be swiveled with its back side folding over the host. Reference to mobile phones or smart phones that adopt the biaxial hinge to swivel the display screen can be found in U.S. patent publication Nos. 20040203532, 20040203535, and 20040209645.
The buttons on a typical mobile phone are organized on a phone keypad. Although they may be used to enter characters through software settings, input operation is inconvenient and data entry is slow. Operation by selecting the menu on the touch screen on the PDA is fast, but data input on the virtual keyboard shown on the display screen or through the hand writing mode takes time that slows down the process and creates inaccuracy. To remedy these problems, external QWERTY keyboards have been developed. But the external QWERTY keyboard is not convenient to carry hence it is not suitable for portable electronic devices. The flip cover design that imitates the notebook computer previously discussed usually has the longer side of the host as the rotational axis of the flipping direction, but the mobile phone generally uses the shorter side of the host as the rotational axis of the flipping direction. Hence the design of the flip cover that imitates the notebook computer does not conform to the general use habit of the mobile phone.
U.S. patent publication No. 20040203517 provides a smart phone with an improved design for the QWERTY keypad. It includes a main body and a sub-body. The main body has a QWERTY keypad on two sides of its surface. The sub-body contains a display screen and a phone keypad. In the mobile phone operation mode, the sub-body covers the QWERTY keypad on one side. In the PDA operation mode, the sub-body may be swiveled horizontally ninety degrees to make the sub-body normal to the main body. Such a design has the striking surface of the QWERTY keypad parallel to the display screen. When placed on the desktop for operation, the display screen on the sub-body is also parallel to the desktop. Users have to lower their heads to see the display screen, which causes physical strain.
In addition, MOTOROLA has introduced a smart phone model MPx(reference can be found in http://www.motorola.com). It has a display screen and a host. The host has a QWERTY keypad and a phone keypad. A detachable hinge is provided so that the display screen can be selectively hinged on a longer side or a shorter side of the host to provide the mobile phone operation mode or the QWERTY keypad input mode for PDA. However, switching is done by detaching and is inconvenient. Moreover, frequent detachment causes wearing of elements and damaging of the hinge. Also, operation of the PDA may be done in handheld touch operation mode and QWERTY keypad input mode. In the handheld touch operation mode the display screen overlaps with the host, and the keypad is hidden on the back side of the display screen to expose the display screen and avoid interrupting operation of the host or mistakenly striking the keypad. The design of the MPx model cannot hide the keypad or overlap the keypad with the host. U.S. Pat. No. 6,728,557 discloses a L-shaped hinge on the juncture of the top side and lateral side of a host to pivotally couple with a flip cover on the juncture of a top edge and side edge thereof. The flip cover may be lifted from the top edge or the side edge to form two different operation modes. Its operation is like providing a flip cover for a mobile phone and notebook computer at the same time. It also has the same drawbacks occurring with the MPx model mentioned above. Namely, in the handheld operation mode for PDA, the keypad cannot be fully hidden under the flip cover, and operation interference and unconsciously hitting of the buttons still occur.
All the conventional techniques mentioned above employ a one-way or biaxial hinge to switch the coupling relationship of the flip cover and the host to provide a mobile phone operation mode or PDA operation mode. The mobile phone operation mode is simpler and can be satisfied by the general flip cover design. The PDA operation mode is more complicated and requires a QWERTY keypad to speed up data entry. To increase the speed of data entry, the keypad and the display screen should form an inclined angle between them to make it easier for users to see the display screen during operation. On the other hand, in the handheld touch operation mode, the host and the flip cover should be overlapped to cover the keypad to facilitate holding and touch operation. All the conventional techniques previously discussed cannot meet these requirements at the same time and provide the optimal operation modes. There is still room for improvement in the design of the PDA phone or smart phone.